Gold miners made significant cuts to their reserves when they reported fourth-quarter earnings earlier this month. That was no surprise, as gold prices dropped 27% in 2013 and the companies made more conservative pricing assumptions for the future.

But silver prices performed even worse than gold last year, plunging a whopping 35%, so it would stand to reason that the silver-focused miners would be slashing reserves as well.

But, so far, that hasn’t been the case.

J.P. Morgan analyst John Bridges pointed out that Pan American Silver Corp., Hecla Mining Co. and Coeur Mining Inc. all boosted reserves in their Q4 results, even as they lowered their price assumptions. He called the reserve increases “striking.”

“Coeur and Pan American have delivered net organic growth in reserves even as the silver prices used have fallen,” he said in a note. “Hecla benefited from including its new Casa Berardi operation in reserves and other assets in resources.”

Coeur’s reserves rose 16%, largely due to additions at its Rochester operation. Hecla has high-quality assets, Mr. Bridges noted, which protects it from big reserve declines. Reserves went up 13% overall, with new ounces added at the Lucky Friday operation. And Pan American raised reserves by 2%, mainly due to exploration success at the La Colorada mine in Mexico.

Hecla used a silver price of US$20 an ounce to calculate reserves this year, making it the most conservative of the three companies. Coeur used US$25, while Pan American used US$22. Silver currently trades at slightly above US$22 an ounce.